1. Field of the Invention
The present invention relates to a flat panel display, and more particularly, to a method and apparatus used to fabricate a flat panel display that simplifies a fabricating process by decreasing a number of patterning process and improving accuracy while aligning a thin film pattern.
2. Discussion of the Related Art
In a recent information society, display devices, specifically flat type display devices, have gained in importance as a visual information communication medium. Fflat panel display devices include liquid crystal display (LCD) devices, field emission display (FED) devices, plasma display panel (PDP) devices and an electroluminescence (EL) displays. Most of these display devices are already available on the market. On the other hand, related art cathode ray tube or braun tube is decreasing its popularity due to bulky size and heavier weight.
One of the flat panel display devices, the liquid crystal display device, is considered to generally satisfy users' needs. Specifically, light weight, thin width, low power consumption, small size, and other advantages of the liquid crystal display device attract many users. In addition, manufactures are able to mass produce liquid crystal display devices. Accordingly, related art cathode ray tubes are being actively replaced by the liquid crystal display device.
As shown in FIG. 1, a related art active matrix type liquid crystal display device, which drives a liquid crystal cell by a thin film transistor (hereinafter, referred to as “TFT”), has an advantage such as a high quality picture and low power consumption. The related art active matrix type liquid crystal display device is rapidly developed into a larger-size having a higher-resolution through an active research and development. The related art active matrix type liquid crystal display device of FIG. 1 has a color filter substrate 22 and a TFT array substrate 23 bonded together with a liquid crystal layer 15 interposed therebetween.
In the color filter substrate 22, a color filter 13 and a common electrode 14 are formed on the rear surface of an upper glass substrate 12. A polarizer 11 is adhered onto the front surface of the upper glass substrate 12. The color filter 13 has red R, green G and blue B color filter layers arranged therein to transmit a light of a specific wavelength range, thereby enabling the display device to display color. A black matrix (not shown) is formed between the adjacent color filters 13. In the TFT array substrate 23, data lines 19 and gate lines 18 cross each other on the upper surface of a lower glass substrate 16, and a TFT 20 is formed at an intersection thereof. A pixel electrode 21 is formed at a cell area between the data line 19 and the gate line 18 on the upper surface of the lower glass substrate 16. The TFT 20 switches a data transmission path between the data line 19 and the pixel electrode 21 in response to a scan signal from the gate line 18, thereby driving the pixel electrode 21. The polarizer 17 is adhered to the rear surface of the TFT array substrate 23.
A liquid crystal layer 15 controls the amount of light transmitted through the TFT array substrate by applied electric field. The polarizers 11 and 17 adhered to the color filter substrate 22 and the TFT substrate 23 transmit a polarized light in any direction, and when the liquid crystal 15 is in a 90° TN mode, their polarizing directions cross each other perpendicularly. An alignment film (not shown) is formed on the liquid crystals at an opposite surfaces to the color filter substrate 22 and the array TFT substrate 23.
A related art fabricating method of the active matrix type liquid crystal display device is divided into a substrate cleaning process, a substrate patterning process, an alignment film forming/rubbing process, a substrate bonding/liquid crystal injecting process, a mounting process, an inspection process, a repair process and other suitable processes. The substrate cleaning process removes impurities (i.e., contaminates a substrate surface of the liquid crystal display device) with a cleaning solution. The substrate patterning process is performed by patterning process of the color filter substrate and a patterning process of the TFT array substrate. The alignment film forming/rubbing process spreads an alignment film over each of the color filter substrate and the TFT array substrate, and rubs the alignment film with a rubbing cloth. The substrate bonding/liquid crystal injecting process bonds the color filter substrate with the TFT array substrate by a sealant and injects liquid crystal and spacers through a liquid crystal injection hole, and then seals up the liquid crystal injection hole. The mounting process connects a tape carrier package (hereinafter, referred to as “TCP”) to a pad part of the substrate, wherein the TCP has an integrated circuit IC such as a gate drive IC and a data drive IC mounted thereon. The drive IC can be directly mounted on the substrate by a chip-on-glass (hereinafter, referred to as “COG”) method or a tape automated bonding (TAB) method. The inspection process includes an electrical inspection which is performed after forming the pixel electrode and the signal lines (i.e., data line and gate lines in the TFT array substrate). An electrical inspection and a macrography are performed after the substrate bonding/liquid crystal injecting process. When the substrate is judged repairable in the inspection process, then the repair process performs a restoration of the substrate. Otherwise, the substrate are disposed as waste.
A thin film material deposited on the substrate is patterned by a photolithography process. The photolithography process is a series of photography process which includes photo-resist spreading, mask aligning, exposure, development and cleaning. However, the photolithography process has several problems, for example, the time required to complete the photolithography process is long, a photo-resist material and a strip solution are greatly wasted, and expensive equipments like an exposure equipment is required.